1. Field of the Invention
The present invention relates to a robot having an obstacle detection unit and a method of controlling the robot. More particularly, to a robot having an obstacle detection unit and a method of controlling the robot capable of maintaining the robot at a constant distance from obstacles.
2. Description of the Related Art
A conventional cleaning robot is an automatic cleaning machine that cleans an area while moving across the area by itself without a user's intervention.
In the conventional cleaning robot, an intake port is integrated with a main body, or is fabricated as a separate part and mounted on the main body. In the case where the intake port is integrated with the main body, the intake port is defined in the lower portion of the main body and is located inside of the outer edge of the main body. Therefore, the location and direction of suction are determined only by the movement of the main body. As a result, it is difficult to realize sufficient cleaning along walls, in areas adjacent to obstacles and in corners.
When the intake port is manufactured as a separate part and is mounted on the main body, an intake tube and an intake nozzle project from the main body, as in a typical canister-type vacuum cleaner. Accordingly, when using the canister-type vacuum cleaner, a user must control the canister-type vacuum cleaner in such a way that the user holds a suction head using his or her hand and sweeps the suction head over an area to be cleaned, so the location and direction of the intake port can be controlled separately from those of the main body, the control algorithm and joint structure thereof are very complicated, and manufacturing cost is high.
Recently, a scheme of manufacturing the intake port separately and mounting the intake port on the main body so that it can freely rotate has been developed. In this case, the free rotation of the intake port is performed such that the intake port is always located perpendicular to the direction of movement or rotation of the main body by frictional force acting on wheels mounted on the intake port and inertia based on the center of gravity, which is located behind the center of rotation of the intake port.
However, when the intake port is configured to freely rotate, the rotational response of the intake port may lag behind the movement or rotation of the main body. Accordingly, a problem occurs in that the cleaning performance thereof is degraded when the direction frequently changes.
Furthermore, since the intake port has a freely rotated structure, it is difficult to clean an uneven area or a carpet. Additionally, it is even more difficult to precisely control the intake port. Thus, there is a problem in that it is difficult to move the intake port close to a wall when cleaning a corner.
Korean Unexamined Patent Publication No. 2006-0003188 discloses a cleaning robot having an intake port mounted to project outside the main body thereof and to be rotatable with respect to the main body. Therefore, the cleaning robot can clean a wide area and can clean near a corner. This above-mentioned disclosure relates to a technology through which the intake port approaches an obstacle, a wall or a corner and performs cleaning. Accordingly, this disclosure does not propose a scheme for controlling the direction of movement of a robot in consideration of the surface state of an obstacle and maintaining a constant distance from the obstacle, even in the case where the surface of the obstacle is uneven.